You need to look up how to properly install gcc, make, cmake and its dependencies.

I've been using VScode with CMake Tools plugin to compile it.

For FFmpeg you need additional -dev modules and pkg-config so that cmake could properly link it:

sudo apt get pkg-config ffmpeg libavcodec-dev libavformat-dev libavdevice-dev libavutil-dev libswresample-dev libswscale-dev

This project is roughly based on bartjoyce streams so you could consult his videos for further information.